Fig. 3: Age model and sampling positions of detrital zircon for cores LV90-8-1 and LV90-9-1.
From: Arctic zircon U-Pb ages reveal multiphase glaciations in East Siberia during the late Quaternary
The color reflectance (a*; a, d)29 of LV90-8-1 and LV90-9-1 were processed with a 5-cm moving average, where yellow points denote selected markers for glacial–interglacial boundary determination (see “Methods”). Glacial periods 1 to 6 are shaded and indicated in green italics. The chronology of core LV90-8-1 and LV90-9-1 is based on AMS 14C dating (green dots) on total organic carbon29 and correlation to adjacent cores PS2757-8 and 29-GC130,31 from the Lomonosov Ridge. Bulk density stratigraphic tie points α1 to α5 from core PS2757-8 and 29-GC130,31 (g, h) are identified in core LV90-8-1 and LV90-9-129 (b, e), indicating good correlation between these cores. Red dots with age text in core 29-GC1 are optically stimulated luminescence (OSL) dating results66. The occurrence of dinocyst Operculodinium centrocarpum from PS2757-8 is marked by green bars, which allowed identification of MIS (marine isotope stage) 3 and MIS 167. The variations in 230Thxs for core PS2757-8 (i) are shown with its “230Thxs extinction age” (~231 ka, early MIS 7) at depth of ~5.9 ± 1.5 m32,33. The blue italic “MIS” refers to the age model from refs. 30, 31, while the orange italic “MIS” refers to the age model from refs. 32,33 (see “Methods”). Sediments with high sand content (usually 10%; c, f) were sampled for detrital zircon U-Pb dating, the postions of which are marked by hexagons with sample names. The thumbnail shows locations of these cores. Basemap of the thumbnailis from the ETOPO Global Relief Model (https://www.ncei.noaa.gov/products/etopo-global-relief-model). NB Nansen Basin, AB Amundsen Basin, LR Lomonosov Ridge, MR Mendeleev Ridge, CB Canada Basin, MB Makarov Basin, AP Alris Plateau, CP Chukchi Plateau, NWR Northwind Ridge. Source data of sand content are provided in Supplementary Data S3.
